linux-kernel - [PATCH] Bluetooth: L2CAP: handle NULL sock pointer in l2cap_sock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20241217211959.279881-1-pchelkin@ispras.ru>
Date: Wed, 18 Dec 2024 00:19:59 +0300
From: Fedor Pchelkin <pchelkin@...ras.ru>
To: Luiz Augusto von Dentz <luiz.dentz@...il.com>,
	Jakub Kicinski <kuba@...nel.org>
Cc: Fedor Pchelkin <pchelkin@...ras.ru>,
	Johan Hedberg <johan.hedberg@...il.com>,
	Marcel Holtmann <marcel@...tmann.org>,
	Ignat Korchagin <ignat@...udflare.com>,
	Kuniyuki Iwashima <kuniyu@...zon.com>,
	Eric Dumazet <edumazet@...gle.com>,
	linux-bluetooth@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	lvc-project@...uxtesting.org,
	netdev@...r.kernel.org,
	stable@...r.kernel.org
Subject: [PATCH] Bluetooth: L2CAP: handle NULL sock pointer in l2cap_sock_alloc

A NULL sock pointer is passed into l2cap_sock_alloc() when it is called
from l2cap_sock_new_connection_cb() and the error handling paths should
also be aware of it.

Seemingly a more elegant solution would be to swap bt_sock_alloc() and
l2cap_chan_create() calls since they are not interdependent to that moment
but then l2cap_chan_create() adds the soon to be deallocated and still
dummy-initialized channel to the global list accessible by many L2CAP
paths. The channel would be removed from the list in short period of time
but be a bit more straight-forward here and just check for NULL instead of
changing the order of function calls.

Found by Linux Verification Center (linuxtesting.org) with SVACE static
analysis tool.

Fixes: 7c4f78cdb8e7 ("Bluetooth: L2CAP: do not leave dangling sk pointer on error in l2cap_sock_create()")
Cc: stable@...r.kernel.org
Signed-off-by: Fedor Pchelkin <pchelkin@...ras.ru>
---
 net/bluetooth/l2cap_sock.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 3d2553dcdb1b..49f97d4138ea 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -1888,7 +1888,8 @@ static struct sock *l2cap_sock_alloc(struct net *net, struct socket *sock,
 	chan = l2cap_chan_create();
 	if (!chan) {
 		sk_free(sk);
-		sock->sk = NULL;
+		if (sock)
+			sock->sk = NULL;
 		return NULL;
 	}

-- 
2.39.5